Comet 12P/Pons-Brooks photographed on March 7, 2024 (Credit: Nielander/ CC0/ Wikimedia Commons)

On April 21, 2024, the 10.5-mile-wide (17 km) Comet 12P/Pons-Brooks, also called "Devil Comet," will make its closest approach to the Sun. As it comes near the star, the comet will brighten significantly and be visible in the western sky an hour after sunset. The icy rock will appear as a fuzzy glowing patch with a faint tail streaking behind.

Pons-Brooks will disappear from the northern skies after April 21. However, observers in the Southern Hemisphere will have several more weeks to catch a glimpse. Their best viewing opportunity will occur on June 2, 2024, when the comet will come within 142 million miles (228 million km) of Earth. Regardless of the location, the celestial event will require a good telescope or a pair of stargazing binoculars. But it may be worth the effort, given that the next sighting of the Devil Comet will not be until 2095.

Why is it called Devil Comet?

Pons-Brooks is a cryovolcanic — or cold volcano — comet. These comets comprise an icy nucleus surrounded by a coma — a layer of gas and dust. When they approach the Sun, the rise in temperature and pressure triggers intense explosions, releasing large amounts of ice and gas into space. The phenomenon is similar to volcanic eruptions on Earth but with frozen materials instead of molten lava.

The comet got its name from the "horns" that appeared after a violent explosion (Credit: Juan Lacruz/ CC-BY-SA 4.0/ Wikimedia Commons)

Pons-Brooks is well-known for its periodic outbursts. But on October 5, 2023, astronomers detected a particularly large explosion. It caused the comet to become much brighter and also develop two horn-like tails. The "horns" have disappeared since, and the comet's recent outbursts have not been as dramatic. However, the nickname has stuck.